JP6323071B2 - Surface condition inspection method, imprint mold manufacturing method, and imprint method - Google Patents

Description

  The present invention relates to a method for inspecting a surface state, a method for manufacturing an imprint mold, and an imprint method.

  Nanoimprint technology as a microfabrication technology uses a mold member (imprint mold) in which a fine concavo-convex pattern is formed on the surface of a substrate, and transfers the fine concavo-convex pattern onto a workpiece such as an imprint resin. This is a pattern formation technique for transferring a fine concavo-convex pattern at an equal magnification (see Patent Document 1). In particular, with the progress of further miniaturization of wiring patterns and the like in semiconductor devices, nanoimprint technology is gaining more and more attention in semiconductor device manufacturing processes and the like.

  As nanoimprint technology, a thermoplastic resin is used as an imprint resin, a heat imprint technology that transfers a fine uneven pattern by applying heat, and a photo-curable resin is used as an imprint resin, and light is irradiated. An optical imprint technique for transferring a fine uneven pattern is known.

  Quartz glass is generally used as a material for the imprint mold used in this nanoimprint technology, particularly optical imprint technology, but the imprint mold composed of quartz glass is releasable from the imprint resin. Is relatively bad. Therefore, when the imprint mold is released from the imprint resin to which the fine concavo-convex pattern is transferred, there is a possibility that a defect is generated in the transfer pattern. In order to solve such problems and improve the mold release performance of the imprint mold, a method of forming a mold release layer so as to cover the fine uneven pattern of the imprint mold has been proposed.

  Further, for the purpose of improving the mold release performance and preventing the transfer pattern from being defective, the transfer pattern made of the imprint resin forms an adhesion layer having good adhesion with the imprint resin on the transfer substrate. A method has also been proposed.

  If such a release layer and an adhesion layer are not formed uniformly, it becomes impossible to prevent the transfer pattern from being defective. Therefore, in order to more effectively prevent the occurrence of defects in the transfer pattern, it is important to accurately grasp the surface state of the release layer on the imprint mold and the adhesion layer on the transferred substrate.

  Since such an adhesion layer or a release layer is formed as a thin film in monolayer units, the surface state of the thin film is quantitatively determined by a general optical method as a method for measuring the surface state of the film. There is a problem that it cannot be accurately grasped.

  Therefore, as a method of grasping the state of the film surface and the like as described above, conventionally, a method of evaluating the surface state using the wettability of the surface of the imprint mold as an index (see Patent Document 2), an AFM cantilever on the film surface A method of evaluating the surface state by using the deflection (displacement) of the cantilever due to the physical force between the tip of the cantilever and the surface of the membrane as an index is described (see Patent Document 3).

US Pat. No. 5,772,905 JP 2011-96708 A JP 2000-346784 A

  In the method described in Patent Document 2, the wettability of the surface of the imprint mold is determined by measuring the contact angle of water droplets or the like dropped on the surface of the imprint mold. As described above, if the contact angle of water droplets on the surface of the imprint mold is measured, the surface state can be grasped, but there is a problem that the surface of the imprint mold is contaminated by adhesion of water droplets or the like. is there.

  In addition, due to the formation of a uniform monomolecular layer on the surface of the substrate to be transferred, imprint mold, etc. used for imprint processing, the transfer layer has a defect. Etc. can be prevented. However, even when a part of the adhesion layer or release layer is formed as a laminated structure or a network structure, it is possible to accurately grasp such a surface state by measuring the contact angle of water droplets or the like. There is a problem that can not be. Since the contact angle is determined by the type of functional group located on the outermost surface of the substrate or the like as the measurement target, the adhesion layer or release layer formed on the surface of the substrate or the like is formed as a monomolecular layer. However, even if the film is formed as a laminated structure or a network structure, the contact angle does not change if the type of the functional group located on the outermost surface is the same.

  In the method described in Patent Document 3, the surface state is grasped by using an AFM cantilever. By using the AFM cantilever, there is no problem of contamination of the surface of the object to be inspected, and it is possible to grasp the film formation state (monomolecular layer, laminated structure, network structure, etc.) such as the adhesion layer and the release layer. However, there is a problem that it is difficult to evaluate the surface state with good reproducibility due to wear of the cantilever or the like.

  In view of the above problems, the present invention can accurately and accurately evaluate the surface state of an object to be inspected without contaminating the surface of the object to be inspected such as an imprint mold or a transfer substrate. It is an object of the present invention to provide a surface condition inspection method that can be performed, and an imprint mold manufacturing method and imprint method using the surface condition inspection method.

In order to solve the above problems, the present invention is a method for inspecting the state of the surface of an object to be inspected, comprising preparing a probe having a curved surface, and applying the curved surface of the probe to the surface of the object to be inspected. And a step of separating the measuring element having the curved surface in contact with the surface of the inspection object from the surface of the inspection object, wherein the inspection object includes one surface and the one surface. An imprint mold in which a fine concavo-convex pattern is provided on any one of the one surface side and the other surface side of a base material having another surface facing the surface, and the surface of the inspection object Is the surface of the release layer formed on the surface on which the fine concavo-convex pattern is provided, and the curved surface of the measuring element is in contact with the surface of the release layer until it is separated from the surface. Measure the load change on the probe and measure the maximum load Determined, on the basis of the correlation between the release performance to the maximum value of the load of the release layer, provide a surface state inspection method and evaluating the release performance of the release layer as the surface condition (Invention 1)

  When the surface of the object to be inspected is in contact with the surface of the object to be inspected, the surface of the object to be inspected (surface molecules (atoms)) and the surface of the object to be inspected (surface molecules (atoms)) Intermolecular (atomic) interaction (intermolecular force) that attracts each other occurs. When the surface of the inspected object that contacts each other and the curved surface of the measuring element are separated from each other, the load applied to the measuring element changes due to the influence of this interaction, and the maximum load depends on the surface condition of the inspecting object. The value fluctuates. Therefore, according to the present invention (Invention 1), the surface state of the object to be inspected can be accurately evaluated by measuring the change in the load applied to the probe and obtaining the maximum value of the load. In addition, according to the present invention (invention 1), the surface of the object to be inspected can be evaluated simply by bringing a measuring element into contact with the surface of the object to be inspected without attaching water droplets or the like. So does the effect of not polluting.

The present invention is a method for inspecting the state of the surface of an object to be inspected, comprising preparing a probe having a curved surface, bringing the curved surface of the probe into contact with the surface of the object to be inspected, and the object to be inspected A step of separating the measuring element having the curved surface in contact with the surface of the object from the surface of the object to be inspected, and the object to be inspected is used in an imprint process using an imprint mold. And a surface to be inspected, wherein the surface of the object to be inspected is one of the one surface and the other surface of the substrate to be transferred. It is the surface of the adhesion layer that is formed, and the change in the load applied to the probe from the time when the curved surface of the probe is brought into contact with the surface of the adhesion layer to the separation is measured, and the maximum of the load is measured. The value used for the imprint process is obtained. Based on the adhesion of the adhesive layer to the print resin and the maximum value of the load, it provides a surface state inspection method and evaluating the adhesion of the adhesive layer as the surface state (invention 2).

A method for inspecting the state of the surface of an object to be inspected, comprising preparing a probe having a curved surface, bringing the curved surface of the probe into contact with the surface of the object to be inspected, and a surface of the object to be inspected Separating the probe having the curved surface from the surface of the object to be inspected, and the object to be inspected has one surface and another surface facing the one surface, A transparent substrate in which a metal layer is formed on any one of the one surface and the other surface, and the curved surface of the measuring element is in contact with the surface of the metal layer until it is separated from the surface. The change in the load applied to the probe is measured to obtain the maximum value of the load, and based on the correlation between the composition of the surface of the metal layer and the maximum value of the load, the surface state of the surface of the metal layer is determined as the surface state. A surface condition inspection method characterized by evaluating a composition is provided. 3). In the said invention (invention 3), based on the correlation of the composition ratio of the metal and oxygen in the surface of the said metal layer, and the maximum value of the said load, the metal and oxygen in the surface of the said metal layer as the said surface state The composition ratio may be evaluated (Invention 4).

In the above invention (Invention 3), the presence or absence of oxidation on the surface of the metal layer as the surface state is evaluated based on the correlation between the presence or absence of oxidation on the surface of the metal layer and the maximum value of the load. (Invention 5).

The present invention is also a method for producing an imprint mold having a fine concavo-convex pattern and at least a release layer formed on the fine concavo-convex pattern, and is substantially the same as the material constituting the imprint mold. A step of forming a film to be inspected of the same material as the release layer on a sample piece of material, and a probe having a curved surface are prepared, and the curved surface of the probe on the surface of the film to be inspected formed on the sample piece Contacting the surface of the film to be inspected, separating the measuring element having the curved surface in contact with the surface of the film to be inspected from the surface of the film to be inspected, and bringing the curved surface of the measuring element into contact with the surface of the film to be inspected A step of measuring a change in load applied to the probe from the time it is separated to obtaining a maximum value of the load, and obtaining a correlation between the maximum value of the load and the film formation condition of the film to be inspected Process and Determining a film forming condition for the release layer based on the correlation, and forming a mold release layer on at least the fine concavo-convex pattern based on the film forming condition for the release layer. An imprint mold manufacturing method is provided (Invention 6 ).

Furthermore, the present invention uses an imprint mold having a fine concavo-convex pattern and at least a release layer formed on the fine concavo-convex pattern, and makes contact with the imprint resin on the substrate to be transferred. Then, an imprint method for transferring the fine concavo-convex pattern onto the substrate to be transferred, wherein an inspection film made of the same material as that of the release layer is formed on a substrate that is substantially the same material as the imprint mold. A step of preparing a test piece formed under the same film formation conditions as the film formation conditions of the release layer in the imprint mold, and a probe having a curved surface are prepared, and the test piece of the test piece is formed on the film to be inspected. A step of bringing the curved surface of the measuring element into contact, a step of separating the measuring element having the curved surface in contact with the surface of the film to be inspected from the surface of the film to be inspected, and the front of the measuring element Measuring a change in the load applied to the measuring element from the time when the curved surface is brought into contact with the surface of the film to be inspected until the curved surface is separated, and determining the maximum value of the load, and using the maximum value of the load as an index A step of evaluating the release performance of the release layer of the imprint mold, and when the release performance of the release layer of the imprint mold satisfies a predetermined standard, the imprint mold is used. Provided is an imprint method, wherein the fine uneven pattern is transferred onto the transfer substrate by bringing the fine uneven pattern into contact with an imprint resin on the transfer substrate (Invention 7 ).

Furthermore, the present invention uses an imprint mold having a fine concavo-convex pattern, contacts the imprint resin on the transfer substrate having an adhesion layer, and makes the fine concavo-convex pattern on the transfer substrate. A film to be inspected having the same material as that of the adhesive layer on a substrate having substantially the same material as that of the substrate to be transferred, the same as the film forming conditions of the adhesive layer on the substrate to be transferred. Preparing a test piece formed under the film forming conditions, preparing a probe having a curved surface, bringing the curved surface of the probe into contact with the film to be inspected of the transfer substrate, The step of separating the measuring element having the curved surface in contact with the surface of the inspection film from the surface of the film to be inspected, and the time between contacting the curved surface of the measuring element to the surface of the inspection film and separating the surface Measuring the change of the load applied to the measuring element to obtain the maximum value of the load, and evaluating the adhesion force of the adhesion layer of the substrate to be transferred using the maximum value of the load as an index, When the adhesion of the adhesion layer of the substrate to be transferred satisfies a predetermined standard, the fine uneven pattern of the imprint mold is brought into contact with the imprint resin on the substrate to be transferred to the substrate to be transferred. Provided is an imprint method characterized by transferring the fine uneven pattern (Invention 8 ).

  In the present invention, “substantially the same material” means that the main materials constituting the base material such as the imprint mold and the substrate to be transferred are at least the same, and the impurities contained in the base material etc. Even if the types and amounts are different, the materials are substantially the same.

  According to the present invention, a surface state inspection that can accurately and accurately evaluate the surface state of the inspection object without contaminating the surface of the inspection object such as an imprint mold or a transfer substrate. A method and an imprint mold manufacturing method and imprint method using the surface condition inspection method can be provided.

FIG. 1 is a process flow diagram showing each step of the surface state inspection method according to one embodiment of the present invention in a side view. FIG. 2 is a graph showing the relationship between the distance between the inspected object / measuring element and the load applied to the measuring element in one embodiment of the present invention. FIG. 3 is a process flow chart showing each process of the imprint mold manufacturing method according to the embodiment of the present invention in a cut end view. FIG. 4 is a process flow diagram showing each process of the imprint method according to the embodiment of the present invention in a cut end view. FIG. 5A is a graph showing the relationship between the film formation time and the adhesion force in the example, and FIG. 5B is a graph showing the relationship between the adhesion force and the maximum load value in the example.

Embodiments of the present invention will be described with reference to the drawings.
[Surface condition inspection method]
FIG. 1 is a process flow diagram showing each step of the surface state inspection method according to the present embodiment in a side view.

  First, an inspection object 1 to be inspected for a surface state and a measuring element 2 having a curved surface 2A are prepared (FIG. 1A), and the curved surface 2A of the measuring element 2 is provided on the surface 1A of the inspection object 1. Contact is made (FIG. 1B).

  In the present embodiment, the inspection object 1 is not particularly limited. For example, the thin film 12 may be formed on the base material 11, or the base material 11 that does not have the thin film 12. There may be. The substrate 11 on which the thin film 12 is formed includes an imprint mold in which a release layer is formed on the surface on which the fine concavo-convex pattern is formed, and a transfer substrate in which an adhesion layer is formed on one surface. Examples thereof include a mask blank in which a hard mask layer such as metal chrome is formed on one surface of a substrate (such as a silicon wafer) or a substrate (such as a quartz glass substrate). Thus, the thin film 12 is a thin layer with respect to the base material 11, and can typically illustrate a release layer, an adhesion layer, a hard mask layer, and the like. Further, as the base material 11 not having the thin film 12, an imprint mold having no release layer, a substrate to be transferred (silicon wafer or the like) having no adhesion layer, etc., a substrate having no hard mask layer (quartz glass substrate or the like) ) And the like. In addition, as the object to be inspected, a sample piece simulating the object to be inspected (for example, on a base material of the same material as an imprint mold, a transfer substrate, a mask blank, etc., under the same processing conditions, a release layer and an adhesion layer Or a sample piece or the like on which a hard mask layer or the like is formed may be used.

  Further, the surface 1A of the inspection object 1 to be substantially inspected is the surface 1A of the thin film 12 if the inspection object 1 is the base material 11 having the thin film 12, and the base material 11 having no thin film 12. If so, it is the surface 1A of the substrate 11. For example, the surface 1A of the inspection object 1 is formed on the surface of the imprint mold (the surface on which the fine concavo-convex pattern is formed) formed on one surface of the transfer substrate (silicon wafer or the like). In addition to the surface of a thin film formed on the surface of a base material such as a hard mask layer formed on one surface of an adhesion layer, a substrate (such as a quartz glass substrate), a substrate (silicon that is not formed) The surface of a transfer substrate such as a wafer, a quartz glass substrate, and the like are also included.

  The measuring element 2 has a curved surface 2A that can be brought into contact with the surface 1A of the object 1 to be inspected. When the surface of the measuring element 2 that contacts the surface 1A of the inspection object 1 is a flat surface, the parallel surface of the inspection object 1 and the surface 1A of the inspection object 1 is parallel when the inspection object 1 and the measuring element 2 are in contact with each other. Depending on the degree, a difference occurs in the intermolecular force acting between them, and the measurement accuracy of the load applied to the probe 2 is lowered. The measuring element 2 has a curved surface 2A, and the curved surface 2A is brought into contact with the surface 1A of the object 1 to be inspected, so that the problem of a decrease in measurement accuracy as described above does not occur.

  The radius of curvature of the curved surface 2A of the probe 2 is not particularly limited, and can be appropriately selected according to the type of the inspection object 1 to be inspected, the size of the region to be inspected, and the like. Moreover, the material of the measuring element 2 can also be suitably selected according to the kind etc. of the to-be-inspected object 1, for example, glass, carbon, rubber | gum etc. can be illustrated. The measuring element 2 may be subjected to surface treatment such as forming a thin film (thin film of the same material as the adhesion layer, the release layer, etc.) on the surface (at least the curved surface 2A).

  Next, the load applied to the measuring element 2 (change in load) is measured while the object 1 and the measuring element 2 are separated so as to raise the measuring element 2 relatively (FIG. 1C). Then, the maximum value of the load is obtained based on the measurement result, and the surface state of the inspection object 1 is evaluated using the maximum value of the load as an index.

  When the surface 1A of the inspection object 1 and the curved surface 2A of the measuring element 2 are brought into contact, a molecule (atom) on the surface 1A of the inspection object 1 and a molecule (atom) of the curved surface 2A of the measuring element 2 are mutually connected. Attracting intermolecular (atomic) interactions occur. Due to this interaction, the load applied to the measuring element 2 changes when the inspection object 1 and the measuring element 2 are separated from each other. Then, the attractive force (intermolecular force) due to the intermolecular (interatomic) interaction does not act between the object 1 and the measuring element 2 when they are separated to a predetermined distance, and the load applied to the measuring element 2 is reduced. It becomes smaller (substantially becomes zero). The magnitude of the attractive force (intermolecular force) acting between the specimen 1 and the probe 2 due to this intermolecular (interatomic) interaction (the magnitude of the load applied to the probe 2 (maximum value)) is It varies depending on the surface condition of the inspection object 1.

  As shown in the graph of FIG. 2, when the object to be inspected 1 and the probe 2 start to be separated, an attractive force (intermolecular force) acts between the two to be separated, and the load applied to the probe 2 gradually increases. growing. And if the to-be-inspected object 1 and the measuring element 2 are separated to the distance where the intermolecular force does not work, the load applied to the measuring element 2 becomes small and becomes substantially zero. Since the maximum value of the load has a correlation with the surface state of the inspection object 1, the surface state of the inspection object 1 can be accurately evaluated using the maximum value of the load as an index.

  For example, when the object to be inspected 1 is a silicon wafer on which an adhesion layer such as a silane coupling agent is formed, the processing conditions for forming an adhesion layer such as a silane coupling agent and the adhesion formed under the processing conditions There is a predetermined correlation between the adhesion of the layers and the maximum value of the load. Therefore, after the probe 2 is brought into contact with the adhesion layer on the silicon wafer, the load applied to the probe 2 is measured while the adhesion layer and the probe 2 are separated from each other, so that the maximum value of the load is used as an index. The adhesion of the adhesion layer on the wafer can be accurately evaluated.

  In addition, the film structure (monomolecular layer structure, laminated structure, network structure, etc.) of the adhesion layer such as a silane coupling agent can be evaluated by the correlation between the adhesion force of the adhesion layer and the maximum value of the load. it can. That is, since there is a predetermined correlation between the film structure of the adhesion layer and the adhesion force, the adhesion force of the adhesion layer can be obtained using the maximum value as an index by obtaining the maximum value of the load. Thereby, the film structure of the adhesion layer can be accurately evaluated.

  The intermolecular (interatomic) interaction acting between the test object 1 and the probe 2 is generated according to the types of molecules on the curved surface 2A of the probe 2 and the molecules on the surface A of the test object 1, for example, , Hydrogen bond, van der Waals force, dipole interaction, ion-ion interaction, and the like.

  The maximum value of the load described above is a device that can measure a change in load applied to the probe 2 due to an attractive force (intermolecular force) acting between two objects (between the object 1 and the probe 2). For example, a surface force measuring device (ESF-5000, manufactured by Elionix) or the like can be used.

  As described above, according to the surface condition inspection method according to the present embodiment, the surface 1A of the inspection object 1 is brought into contact with the surface 1A of the inspection object 1, and then the two surfaces are separated from each other. Since the state can be accurately evaluated, the surface 1A of the inspection object 1 is not contaminated. Further, since the curved surface 2A of the probe 2 is simply brought into contact with the surface 1A of the inspection object 1, the curved surface 2A of the inspection element 2 is not worn, and the surface state of the inspection object 1 is accurately determined. It can be evaluated with good reproducibility.

[Imprint Mold Manufacturing Method]
Next, the manufacturing method of the imprint mold in this embodiment is demonstrated, referring drawings. FIG. 3 is a process flow diagram showing the imprint mold manufacturing method according to the present embodiment in a cut end view.

  First, a transparent substrate 31 such as a quartz substrate having a hard mask layer 32 made of metallic chrome or the like formed on one surface 31A is prepared as an imprint mold substrate 3 (see FIG. 3A). Then, the surface state of the imprint mold substrate 3, that is, the surface state of the surface 3 </ b> A of the hard mask layer 32 is evaluated by the surface state inspection method according to the present embodiment described above. In the present embodiment, “transparent” means that the transmittance of light having a wavelength of 300 to 450 nm is 85% or more, preferably 90% or more, and particularly preferably 95% or more.

  The hard mask layer 32 formed on one surface 31A of the transparent substrate 31 such as a quartz substrate is etched in a later process, and a hard mask pattern 32P for etching the transparent substrate 31 such as a quartz substrate (FIG. 3C). Reference). Since the hard mask pattern 32P is formed with high accuracy, an etching process using the hard mask pattern 32P as a mask can be performed with high accuracy, and the fine uneven pattern 33 (see FIG. 3 (D)) can be formed. Here, depending on the surface state of the hard mask layer 32, the accuracy of the hard mask pattern 32P (see FIG. 3C) may be reduced. For example, when the hard mask layer 32 is made of metal chromium, the metal chromium may be oxidized over time. If the metallic chromium is oxidized, the etching rate of the hard mask layer 32 varies, so that the etching accuracy decreases. Therefore, by evaluating the surface state of the hard mask layer 32, the hard mask layer 32 can be etched at a predetermined etching rate to form a highly accurate hard mask pattern 32P. It is possible to manufacture the imprint mold 30 (see FIG. 3D).

  When the surface state of the hard mask layer 32 is evaluated by the surface state inspection method and the surface state is evaluated as good, a resist pattern RP is formed on the hard mask layer 32 by a photolithography method or the like (FIG. 3 (B)).

  Next, the hard mask layer 32 is etched (dry etching) using the resist pattern RP as a mask to form a hard mask pattern 32P (see FIG. 3C). Since the surface condition of the hard mask layer 32 is evaluated to be good (the metal chromium constituting the hard mask layer 32 is not oxidized) by the surface condition inspection method described above, the etching process is performed at a predetermined etching rate. A high-precision hard mask pattern 32P can be formed.

  Finally, the transparent substrate 31 is etched (dry etching) using the hard mask pattern 32P as a mask to form the fine uneven pattern 33, and then the hard mask pattern 32P is removed (see FIG. 3D). Since the hard mask pattern 32P is formed with high accuracy, the fine concavo-convex pattern 33 formed using the hard mask pattern 32P as a mask is also formed with high accuracy. Therefore, according to the imprint mold manufacturing method of the present embodiment, it is possible to manufacture the imprint mold 30 having the highly accurate fine concavo-convex pattern 33.

[Imprint method]
Next, an imprint method according to this embodiment will be described. FIG. 4 is a process flow diagram showing the imprint method in the present embodiment in a cut end view.

  First, a transfer substrate 40 used in the imprint method and an imprint mold 50 having a fine uneven pattern 51 and having a release layer 52 formed on the surface on which the fine uneven pattern 51 is formed are prepared. (See FIG. 4A), the surface state of the imprint mold 50 and the surface state of the transferred substrate 40 are evaluated by the surface state inspection method according to this embodiment.

  When the surface states of the imprint mold 50 and the transferred substrate 40 are inspected by the surface state inspection method according to the present embodiment, the measuring element 2 (see FIG. 1) particularly contacts the surfaces of the imprint mold 50 and the transferred substrate 40. In the step (see FIG. 1B), the area other than the area where the fine uneven pattern 51 of the imprint mold 50 is not formed and the transfer area of the transferred substrate 40 (area where the pattern is formed by the imprint method). It is preferable to bring the probe 2 into contact with the region. For example, it is a region outside the region where the fine uneven pattern 51 of the imprint mold 50 is formed, and is a region in contact with the imprint resin during imprint processing, or a region near the outer edge of the substrate 40 to be transferred. The measuring element 2 is preferably brought into contact with an area where no pattern is formed by the imprint method.

  The transfer substrate 40 can be appropriately selected according to the purpose of forming a pattern by the imprint method according to the present embodiment. The transfer substrate 40 has a thin film 42 formed on one surface 41A of the base 41. Alternatively, a base material 41 that does not have the thin film 42 may be used. Examples of the substrate 40 to be transferred include a transparent substrate such as a quartz substrate having a hard mask layer such as metallic chromium formed on one side, and a semiconductor substrate such as a silicon wafer having an adhesion layer formed on one side. Can do.

  By the surface state inspection method according to the present embodiment, both the surface state of the imprint mold 50 and the surface state of the transferred substrate 40 are suitable for imprint processing (for example, the mold release performance of the release layer 52 is desired. The imprint resin 61 is applied onto the transfer substrate 40, and the fine uneven pattern of the imprint mold 50 is evaluated. 51 and the imprint resin 61 are brought into contact with each other, and then the imprint resin 61 is cured (see FIG. 4B).

  On the other hand, when it is evaluated that the surface state of the transfer substrate 40 is not suitable for the imprint process, another transfer substrate 40 whose surface state is suitable for the imprint process is prepared, and the imprint process (FIG. 4B )). When it is evaluated that the surface state of the imprint mold 50 is not suitable for the imprint process, the imprint process (see FIG. 4B) is performed after the release layer 52 of the imprint mold 50 is re-formed. Run.

  Finally, the imprint mold 50 is peeled from the cured imprint resin 61 (see FIG. 4C). Thereby, the fine concavo-convex pattern 51 of the imprint mold 50 can be transferred to the imprint resin 61 on the transfer substrate 40.

  According to the imprint method in the present embodiment described above, the surface state of the imprint mold 50 and the surface state of the transferred substrate 40 can be evaluated by the surface state inspection method according to the present embodiment. Only the transferred substrate 40 having an unsuitable surface state can be excluded, and an imprint mold 50 having a surface state suitable for imprint processing can be used. As a result, the fine uneven pattern 51 of the imprint mold 50 can be transferred to the imprint resin 61 with high accuracy without causing a pattern defect or the like.

  In particular, when the imprint process using the imprint mold 50 is continuously performed, the surface state of the imprint mold 50 changes. That is, the mold release performance of the mold release layer 52 provided on the surface of the imprint mold 50 (the surface on which the fine concavo-convex pattern 51 is formed) may deteriorate due to continuous implementation of the imprint process. In such a case, the surface state of the imprint mold 50 (the release performance of the release layer 52) is confirmed by the surface state inspection method according to the present embodiment, so that highly accurate imprint processing is continuously performed. It becomes possible to do.

  The embodiment described above is described for facilitating understanding of the present invention, and is not described for limiting the present invention. Therefore, each element disclosed in the above embodiment is intended to include all design changes and equivalents belonging to the technical scope of the present invention.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated further in detail, this invention is not limited to the following Example at all.

[Example 1]
[Correlation between deposition time and adhesion]
<Formation of adhesion layer>
A silane coupling agent (KBM-5103 (3-acryloxypropyltrimethoxysilane, manufactured by Shin-Etsu Chemical Co., Ltd.)) is formed on one surface of a silicon wafer (diameter 150 mm) by a vapor deposition method to form an adhesion layer. did. The film formation time (evaporation time) was 5 minutes (Sample 1).
Except for changing the film formation time (evaporation time) as shown in Table 1, an adhesion layer was formed on one surface of the silicon wafer in the same manner as Sample 1 (Samples 2 to 5).

<Measurement of adhesion>
Silicon wafers of samples 1 to 5 in the same manner as described in "Measurement of Adhesive Force Between Mold and Photocurable Resin In Imprint Technology; Jpn. Appl. Phys. Vol. 41 (2002) pp. 4194-4197" The adhesion strength (N) of the adhesion layer was measured. That is, two silicon wafers of Samples 1 to 5 were prepared, the adhesion layers were opposed to each other, and a photocurable resin was interposed between them. And after hardening the said photocurable resin, one silicon wafer is peeled from photocurable resin, the maximum load (N) at the time of peeling is measured, and it is each sample (samples 1-5). It was set as the adhesive force (N).

[Correlation between maximum load and adhesion]
<Measurement of maximum load value>
A probe having a glass sphere (φ1 mm) at the tip is prepared as a measuring element, and the surface force measuring device (ESF-5000) manufactured by Elionix Co. A change in load applied to the probe was measured while the adhesion layer of the silicon wafer and the glass sphere were separated from each other, and a maximum load value (μN) was measured from the change in the load. The relationship between the film formation time (min) and the adhesion force (N) and the relationship between the maximum load value (μN) and the adhesion force (N) are shown in the graph of FIG.

  As is clear from the graphs shown in FIGS. 5A and 5B, it was confirmed that there is a predetermined correlation between the adhesion layer deposition time and the maximum load value. Generally, in order to perform a highly accurate imprint process without causing pattern defects, the adhesion of the adhesion layer needs to be 75 N or more. Therefore, using the maximum load value measured by the surface condition inspection method according to the present embodiment as an index, and using the substrate to be transferred having the maximum load value of 160 μN or less for imprint processing, high-precision imprint processing can be performed. It can be evaluated that it is possible. In addition, by forming an adhesion layer on the transfer substrate under the processing conditions (film formation time) using the maximum load value as an index, a transfer substrate capable of high-precision imprint processing can be manufactured. Can be evaluated.

  Further, in the graph shown in FIG. 5B, the maximum load value of the sample 5 is significantly increased as compared with the maximum load value of the samples 1 to 4. The surface structure (chemical structure) of the adhesion layer of Sample 5 was evaluated by measuring the surface roughness of the adhesion layer using an atomic force microscope (AFM). When the surface roughness of the surface of the adhesion layer is small, it can be evaluated that the adhesion layer is formed as a monomolecular layer. When the surface roughness is large, the silane coupling constituting the adhesion layer It can be evaluated that the reaction of the agent is promoted, and the adhesion layer is formed as a higher order structure such as a network structure or a back gas phase structure. As a result of the measurement, the adhesion layer of Sample 5 had a larger surface roughness than the adhesion layers of Samples 1 to 4, and the presence of convex portions having a height of 5 nm or more was confirmed on the surface of the adhesion layer. Projections having a height of 5 nm or more can cause transfer defects. That is, in Sample 5, it can be evaluated that the adhesion layer is formed as a higher order structure such as a network structure or a laminated structure. From this, it is possible to evaluate the chemical structure (monomolecular layer structure, laminated structure, network structure, etc.) of a thin film such as an adhesion layer using the maximum load value obtained by the surface condition inspection method according to this embodiment as an index. Became clear.

  INDUSTRIAL APPLICABILITY The present invention is useful as a method for inspecting and evaluating the surface state of an imprint mold or a silicon wafer used in a nanoimprint process for forming a fine uneven pattern on a semiconductor substrate or the like in a semiconductor device manufacturing process. .

DESCRIPTION OF SYMBOLS 1 ... Test object 1A ... Surface 2 ... Measuring element 2A ... Curved surface

Claims (8)

A method for inspecting the surface state of an object to be inspected,
Preparing a probe having a curved surface, and contacting the curved surface of the probe with the surface of the object to be inspected;
Separating the measuring element having the curved surface in contact with the surface of the inspection object from the surface of the inspection object,
The inspected object is provided with a fine concavo-convex pattern on one of the one surface side and the other surface side of a base material having one surface and another surface facing the one surface. An imprint mold,
The surface of the object to be inspected is the surface of the release layer formed on the surface on which the fine concavo-convex pattern is provided;
The change of the load applied to the measuring element from the time when the curved surface of the measuring element is brought into contact with the surface of the release layer to the time when the measuring element is separated is obtained to obtain the maximum value of the load, and the release layer is separated. A surface condition inspection method , wherein the mold release performance of the mold release layer is evaluated as the surface condition based on a correlation between mold performance and the maximum value of the load . A method for inspecting the surface state of an object to be inspected,
Preparing a probe having a curved surface, and contacting the curved surface of the probe with the surface of the object to be inspected;
Separating the measuring element having the curved surface in contact with the surface of the inspection object from the surface of the inspection object;
Have
The inspection object is a substrate to be transferred having one surface and another surface opposite to the one surface, which is used in an imprint process using an imprint mold,
The surface of the object to be inspected is a surface of an adhesion layer formed on one of the one surface and the other surface of the substrate to be transferred;
The change of the load applied to the measuring element from the time when the curved surface of the measuring element is brought into contact with the surface of the adhesion layer to the time when the measuring element is separated is obtained to obtain the maximum value of the load, and used for the imprint process. based on the adhesion of the adhesive layer to the imprinting resin and the maximum value of the load, the front surface state inspecting how to and evaluating the adhesion of the adhesive layer as the surface state. A method for inspecting the surface state of an object to be inspected,
Preparing a probe having a curved surface, and contacting the curved surface of the probe with the surface of the object to be inspected;
Separating the measuring element having the curved surface in contact with the surface of the inspection object from the surface of the inspection object;
Have
The inspection object is a transparent substrate having one surface and another surface opposite to the one surface, and a metal layer is formed on one of the one surface and the other surface. ,
Measure the change of the load applied to the measuring element from the time when the curved surface of the measuring element is brought into contact with the surface of the metal layer until it is separated, and obtain the maximum value of the load, and the composition of the surface of the metal layer and on the basis of the correlation between the maximum value of the load, the front surface state inspecting how to and evaluating the composition of the surface of the metal layer as the surface state. The composition ratio of metal and oxygen on the surface of the metal layer as the surface state is evaluated based on the correlation between the composition ratio of metal and oxygen on the surface of the metal layer and the maximum value of the load. The surface state inspection method according to claim 3. The presence or absence of oxidation on the surface of the metal layer as the surface state is evaluated based on the correlation between the presence or absence of oxidation on the surface of the metal layer and the maximum value of the load. Surface condition inspection method. A method for producing an imprint mold having a fine concavo-convex pattern and a release layer formed on at least the fine concavo-convex pattern,
Forming an inspected film of the same material as the release layer on a sample piece of substantially the same material as the material constituting the imprint mold;
Preparing a probe having a curved surface, and contacting the curved surface of the probe with the surface of the film to be inspected formed on the sample piece;
Separating the measuring element having the curved surface in contact with the surface of the film to be inspected from the surface of the film to be inspected;
Measuring a change in load applied to the measuring element between the time when the curved surface of the measuring element is brought into contact with the surface of the film to be inspected and the distance from the surface to obtain a maximum value of the load;
Obtaining a correlation between the maximum value of the load and the film forming conditions of the film to be inspected;
Determining film forming conditions for the release layer based on the correlation;
And a step of forming a release layer on at least the fine concavo-convex pattern based on the film forming conditions of the release layer. Using the imprint mold having a fine concavo-convex pattern and at least a release layer formed on the fine concavo-convex pattern, the imprint resin on the substrate to be transferred is brought into contact with the fine concavo-convex pattern, and the transferred object An imprint method for transferring the fine uneven pattern on a substrate,
A film to be inspected having the same material as the release layer is formed on a base material having substantially the same material as the imprint mold under the same film formation conditions as the film formation conditions of the release layer in the imprint mold. Preparing a test piece comprising:
Preparing a probe having a curved surface, and contacting the curved surface of the probe with the film to be inspected of the test piece;
Separating the measuring element having the curved surface in contact with the surface of the film to be inspected from the surface of the film to be inspected;
Measuring a change in load applied to the measuring element between the time when the curved surface of the measuring element is brought into contact with the surface of the film to be inspected and the distance from the surface to obtain a maximum value of the load;
A step of evaluating the release performance of the release layer of the imprint mold using the maximum value of the load as an index,
When the release performance of the release layer of the imprint mold meets a predetermined standard, the imprint mold is used to bring the fine concavo-convex pattern into contact with the imprint resin on the transfer substrate. An imprint method comprising transferring the fine concavo-convex pattern onto a transfer substrate. An imprint method using an imprint mold having a fine concavo-convex pattern, bringing the fine concavo-convex pattern into contact with an imprint resin on a transfer substrate having an adhesion layer, and transferring the fine concavo-convex pattern onto the transfer substrate. There,
A test in which a film to be inspected having the same material as that of the adhesion layer is formed on a base material having substantially the same material as the substrate to be transferred under the same film formation conditions as those for the adhesion layer in the substrate to be transferred. Preparing a piece;
Preparing a probe having a curved surface, bringing the curved surface of the probe into contact with the film to be inspected of the substrate to be transferred; and
Separating the measuring element having the curved surface in contact with the surface of the film to be inspected from the surface of the film to be inspected;
Measuring a change in load applied to the measuring element between the time when the curved surface of the measuring element is brought into contact with the surface of the film to be inspected and the distance from the surface to obtain a maximum value of the load;
A step of evaluating the adhesion force of the adhesion layer of the substrate to be transferred using the maximum value of the load as an index,
When the adhesion of the adhesion layer of the substrate to be transferred satisfies a predetermined standard, the fine uneven pattern of the imprint mold is brought into contact with the imprint resin on the substrate to be transferred to the substrate to be transferred. An imprint method comprising transferring the fine concavo-convex pattern.

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